514 BULLETIN 82, UNITED STATES NATIONAL MUSEUM. 



The orals are rather narrow, with the tips somewhat produced; the proximal 

 border is approximately hemispherical, and the sides converge to a rounded tip; the 

 central portion is very slightly depressed. 



The most developed specimen measures 3.5 mm. in total length, the crown 

 being 0.7 mm. long. 



The stem is composed of 17 columnals and a terminal stem plate. 



The first five columnals are very short and lenticular, the sixth slightly longer 

 than broad, the seventh longer than the sixth, and the eighth the longest, nearly 

 four times as long as broad ; the following very slowly decrease in length distally ; 

 the columnals are cylindrical, with only slight traces of terminal enlargement. 



The terminal stem plate is slightly lobate. 



The basals are much reduced in size. 



The radials are unusually large, approximately square with rounded angles, 

 and are in contact laterally through the slightly truncated lateral angles. 



The large and conspicuous radianal, which is very broadly oval, almost cir- 

 cular, reaches nearly to the middle of the IBr t distally and to the left as far 

 as half way between the posterior interradial suture and the base of the left 

 posterior IBr t ; the left distal edge of the right posterior radial is cut away in a 

 broad curve beneath it from the base of the IBr t to its junction with the left 

 posterior radial. 



On the distal border of the radial circlet in each of the interradial angles 

 there lies a rhombic interradial which distally reaches to the level of the base 

 of the IB^; the posterior interradial (anal a;) is displaced to the left by the 

 radianal, so that it spans the distance between that plate and the left posterior IBr^ 



About three brachials are present, they and the IBr 2 being accompanied 

 by extremely narrow and delicate covering plates. 



The IBr series and the brachials are unusually slender. 



COMISSIA HARTMEYERI. 



On the cirri of the eight specimens of this species collected at Erg Tor, Gulf 

 of Suez, by Dr. Robert Hartmeyer, were a number of pentacrinoids. 



COMANTHUS WAHLBERGII. 



On a specimen of this species in the British Museum from the Cape of Good 

 Hope I found attached to the cirri 13 pentacrinoids. 

 The columnals in these pentacrinoids number 17. 



COMACTINIA MERIDIONALIS. 

 Fig. 941, p. 5-19, and part 1, figs. 408, 411, 412, p. 317; and pi. 4, fig. 548. 



After the discovery of the pentacrinoids of the species of the genus Antedon 

 the stalked larvae of Comactinia meridonalis were the next to be reported. During 

 the residence of Prof. Louis Agassiz at Charleston, South Carolina, he collected 

 some specimens of this species on the cirri of which were growing pentacrinoirl 



